Gadget Freak Jr.: Manned Electric Helicopter

The "e-volo," an electric-powered multicopter, took its first test flight in Germany last month. So called because it has 16 rotors, the 176-pound machine is powered by lithium-ion batteries.

It broke into the mainstream press Thursday with a report on MSNBC.com. A quick online search reveals that Thomas Senkel, one of the developers, posted his own video right after the flight:

Senkel and his partners, Stephan Wolf and Alexander Zosel, run a company called e-volo in Karlsruhe, Germany. Senkel writes on his site that he did all the mechanical and electrical construction on the machine, and that he's a specialist in electric drives and ultralights. Wolf, who is listed on the site as e-volo's CEO, wrote the code for the on-board flight computer. Zosel, a paragliding enthusiast and pilot like Senkel, handles the company's marketing.

As Senkel writes on e-volo's home page and in the closing titles of the video:

At the end of October, 2011, Thomas Senkel of e-volo had completed a series of unmanned tests and was ready for the first manned flight on an airstrip in the southwest of Germany. The flight lasted one minute and 30 seconds, after which [he] stated: "The flight characteristics are good natured. Without any steering input it would just hover there on the spot."

Senkel and his team describe the technology behind the e-volo in this description, pulled from his site:

The e-volo's sixteen propellers allow it to take off and land similar to a helicopter. Its massive plus points compared to a helicopter are the simplicity of its engineered construction without complicated mechanics and its redundant engines. Should anything go wrong, e-volo can still safely land even if up to four of its sixteen motors should fail. Flight time can last between ten to thirty minutes, depending on the payload and the capacity of the lithium batteries. With an empty weight at 80 kg (including batteries), e-volo fits into the class of ultralights... E-volo can use a safety parachute, as there are no propellers blocking the deployment area above.
The propellers create the full lift, and are also responsible for balancing the device on all three axes only by independent speed control of the motors. Unlike the rotor of a helicopter, the propellers dont´t have any pitch control and therefore no wear. These factors make the multicopter mechanically simple, with close to no maintenance necessary.

Competitively speaking, the Frenchman Pascal Chretien would apparently have a claim predating Senkel's to being the first pilot of a manned electric helicopter. His ultralight, described here on Gizmag.com, has two main rotors and uses brush DC motors. (There's no YouTube videos of Chretien's machine, and the Gizmag article is copyrighted, so I'm just linking to it.)

My Take
The e-volo is an impressive example of professional-level tinkering, with the additional element of smart ultralight engineering, in terms of the light weight achieved. Whether it's a practical device for everyday flight is another story entirely.

One can't help but draw comparisons to the James Bond rocket pack from the 1965 movie Thunderball. In the real world, one could point to the Bell Rocket Belt, also of 1960s vintage, from Bell Aerospace.

Senkel's verbiage about pilot safety relative to the propeller got me thinking about a propeller-powered car I saw on that cable TV car show hosted by the guy with the handlebar mustache.

A quick YouTube search revealed it's a 1932 Helicron, which is powered by a four-cylinder, air-cooled propeller. (As is the driver -- air-cooled, that is.) Below is the video. How many severed fingers this vehicle wrought is lost to history. And no, that's not a Pilates ball beneath the e-volo's pilot.

A failure spread around the pilot would still allow landing. All in one arm could wind up being hard to mannage, although still possible.

It does seem that a device like this would be within the capabilities of many builders, even though no information about the motors or props is provided. The concept is quite interesting, and I can see a possibility of using an onboard engine driven generator to provide a much longer flight time, or a hybrid version for when it needs to be quite part of the time.But I do need to find out about those motors and props.

The comment about "can still safely land even if up to four of its sixteen motors should fail" is nonsense. If you look at the design studies the four arms are meant to be folding, so the most likely failures will be in the communication link or power link at the joint (or the joint itself). Failure of four motors on one arm would be catastrophic (and rapidly so).

Also in the design studies is a three arm 12 rotor design. This probably the preferred design, one would assume the fewer rotors would have longer span and therefore more aerodynamic efficiency.

It's a fun idea though, I can see myself dodging traffic in three dimensions on my morning commute :-).

This is a nifty vehicle, but it's clear why it didn't take off (pun intended). No reverse alone presents a big problem. I would imagine wind is a tad rough on passengers. I wonder how its energy consumption compares to the internal combustion engine. My guess is the helicron uses more energy per mile at an equivalent speed. It looks fairly inefficient. But maybe not.

Thiis has a very interesting video, although I would rather have not had so much bandwidth taken up by the dramatic sound track. Those are quite small motors, it appears. It was not clear what the mechanism is for controlling the flight direction, that would be interesting to see.

It looks a bit like a project that others could duplicate, which could be the start of something big. Really big indeed.

Are you able to provide additional information about the voltages and power levels, and anything else?

Great report and such an interesting subject. Very interesting design. I know there are some drones with electrical motors used in Israel, but clearly not the size and design like that with multi motors. I agree that we need to see some controlled motion, rotation and direction controll.

It's a pretty impressive achievement, but maybe not a game-changer. Hovering and station-keeping is good, but I'd want to see some evidence of direction control, turning, and straight-line movement. Can it rotate on its own vertical axis (a useful feature of ordinary helicopters)? The noise of 16 uncorrelated propellors is an interesting sound.

And those guys better stick to engineering -- the video production was pretty hilarious, particularly the uber-dramatic style of the opening, and the choice of music.

This is indeed interesting! A few more details would help, but what is there seems almost like enough for others to duplcate the thing. I can see that stability would require close control of motor speeds, and I do wonder just a bit about how to turn and steer the thing. It sort of looks a bit like the helicopter windmill written up a few weeks ago, which could be flown up to where the airflow was much higher, at which point it would serve as a generating windmill. So we do have a really interesting concept here.

Eleven years ago one of those rare, brilliant moments emerged from the crack staff of Design News: Let’s put the tinkerers among our audience community to work in designing and building some truly wacky devices. And Gadget Freak was born.

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